sferosytoosi

Sferosytoosi, or spherocytosis, refers to a group of red blood cell disorders characterized by the presence of spherocytes in the peripheral blood. Spherocytes are sphere-shaped red blood cells with reduced membrane surface area relative to their volume, making them less deformable and more prone to being removed by the spleen. The condition is most commonly hereditary but can also be autoimmune.

Hereditary spherocytosis is the most frequent form and results from mutations in genes encoding red blood cell membrane proteins, such as ANK1 (ankyrin-1), SPTB (beta-spectrin), SPTA1 (alpha-spectrin), SLC4A1 (band 3), and EPB42 (protein 4.2). These defects weaken the cytoskeletal network, causing loss of membrane surface and the formation of spherocytes. Autoimmune spherocytosis occurs when autoantibodies target red blood cell membrane components, promoting extravascular hemolysis.

Clinical features range from mild to moderate hemolytic anemia with reticulocytosis, jaundice, splenomegaly, and an increased risk of pigmented gallstones. Blood tests commonly show elevated mean corpuscular hemoglobin concentration (MCHC), indirect (unconjugated) bilirubin, and LDH with reduced haptoglobin. Peripheral smears reveal spherocytes, and the direct antiglobulin (Coombs) test helps distinguish hereditary from autoimmune forms. Osmotic fragility testing and flow cytometry–based assays (such as eosin-5′-maleimide binding) support diagnosis.

Treatment varies by severity. Mild cases may require observation and folic acid supplementation. In hereditary HS with significant hemolysis, splenectomy after age about five to six can reduce hemolysis, with vaccination and education to mitigate post-splenectomy infection risk. Autoimmune spherocytosis is managed by addressing the underlying immune process.